Penning-trap mass spectrometry and mean-field study of nuclear shape coexistence in the neutron-deficient lead region


Manea V., Ascher P., Atanasov D., BARZAKH A. E. , Beck D., Blaum K., ...More

PHYSICAL REVIEW C, vol.95, no.5, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 95 Issue: 5
  • Publication Date: 2017
  • Doi Number: 10.1103/physrevc.95.054322
  • Title of Journal : PHYSICAL REVIEW C

Abstract

We present a study of nuclear shape coexistence in the region of neutron-deficient lead isotopes. The midshell gold isotopes Au-180,Au-185,Au-188,Au-190 (Z = 79), the two long-lived nuclear states in At-197 ( Z = 85), and the neutron-rich nuclide At-219 were produced by the ISOLDE facility at CERN and their masses were determined with the high-precision Penning-trap mass spectrometer ISOLTRAP. The studied gold isotopes address the trend of binding energies in a region of the nuclear chart where the nuclear charge radii show pronounced discontinuities. Significant deviations from the atomic-mass evaluation were found for Au-188,Au-190. The new trend of two-neutron separation energies is smoother, although it does reveal the onset of deformation. The origin of this effect is interpreted in connection to the odd-even staggering of binding energies, as well as theoretically by Hartree-Fock-Bogoliubov calculations including quasiparticle blocking. The role of blocking for reproducing the large odd-even staggering of charge radii in the mercury isotopic chain is illustrated.